This is a great way to derail the build. I thought these were supposed to fit. The covers are sitting on the Polylocks. Any options? I don't want tall valve covers. I like the Chevy ones I have. Even Summit says they fit the short covers. F' sakes. Strange thing is it looks like I need 1.94 inches of height but I have 2.19. not sure where it's hanging up if that's the case.

 

Upon further investigation it looks like it's hanging up on the rocker tip. Wonderful. Is there a specific spacer for these covers or will the perimeter ones work?

 

Show us a photo of exactly what doesn't fit.

Can't believe a rocker tip doesn't fit, unless you've got the VCs backwards. Int side is NOT the same as exh side, even though it looks close to the inattentive eye.

 

They're full roller. Can't get them backwards. They're all 1.6. I don't believe there is a exhaust or intake specific one. I doubled the gaskets and they fit. So I ordered a valve cover that's a 1/4" taller

 

He means having the driver and passenger side valve cover reversed.

 

Right then. I'm an idiot. No, they definitely are not reversed. I put a boroscope camera through the oil hole and saw the rocker touching the top of the cover. They were marked when they came off and I also took photos of where everything was. L/H side has the oil cap.

 

i have a set under stock vortec covers on vortec heads. I could have used the stock covers on my aluminum heads that have 0.100 longer valves, but the head was not machined correctly on the valve cover rails to allow it. They left the full boss for the perimiter bolts. Several manufacturers leave their dual drilled heads that way and the stock stamped covers will not go on.

I ended up with slightly taller cast aluminum covers and having to grind on the ac bracket.

 

I have these preforms on my fastburn heads w lt4 roller rockers. They fit and have clearance. That said, if they're not perfectly centered the hit the rockers. It's a tight fit.

 

I have 1.6rr Scorpion's and they fit under my LT1 valve covers just fine. The LT1 VC's aren't much different than TPI the valve covers found on roller SBC's with center bolts.

 

I guess being aluminium the strength has to come from some added bulk.
A quick look and it seems some of the bulk is in the height of the arm.


Check out the height and compare it to the COMP rockers below.




As that where the contact is on yours. Right above the roller?
These COMP rockers fit under my stock Vortec valve covers on my Vortec heads. The only trimming required was along the brace that forms the tube for the valve cover bolt to pass through. The shoulder of the rocker body at the trunnion boss made contact with that rail/brace,
As it is, the clearance is paper thin but there's no contact.
This doesn't solve your dilemma (although it was reported that the COMP's do fit) but it shows how fine the margins are.

 

That's exactly where my contact point was

 

I can see how in comparison it would be.
But below...

A lot of variables between with all of the bits involved.
You owe it to yourself to know that's exactly where the contact is. It wouldn't hurt to assemble a couple of valves on a couple of cylinders and tighten down the valve covers. Spin it over by hand and look for witness marks.
Something as simple as a double thick gasket might resolve the problem.

 

I can't tighten down the cover because it sits off the head, however when I temporarily double the gasket they seemed fine. So I ordered up a set of covers that are a 1/4 inch taller.

 

If your heads have (non OEM stock length) +.100" longer valves then the top of a rocker arm over the tip is going to be also +.100" higher when the valve is closed.
This also will effect where the roller tip contact point is on the valve tip as the inclined longer than stock valve does move the tip of the valve towards towards the rocker stud.

 

Ahh now herein lies the problem.. I have a set of Flow-Tek aluminum heads. The valves are definitely longer. I did manage to get away with stock length hardened push rods though. The tips sweep about .060 over the valve center. I guess the stock height cover fits a stock setup with rollers. This makes sense now.

 

Same here. Never had an issue with clearance.

 

Are you running a factory head setup? It must be the different valve stem length in my setup.

 

I've a set of RHS Vortecs that use a .100" longer valve (It made valve train geometry a pain the *** I should add).
I don't recall if I used my stock valve covers on those heads as presently I've got Proform diecast covers. But those heads are on the workbench at the moment and have yet to be reassembled. Once I get that far, I'll try the OEM covers. If nothing else, your original question may have a definitive answer.
Roller rockers under a stock cover with factory heads. Yes.
Roller rockers under a stock cover with aftermarket heads. Undetermined.

 

I just installed the proform cast covers myself. They're a 1/4“ taller. Seem to be working now. They sat down this time.

 

On a similar note, I've also got a set of GM's diecast valve covers that looks to be a standard height. The original owner had ground reliefs in to the underside for roller rocker clearance. Or at least that's my assumption. This is something I never paid attention to as those covers came my way free of charge and they're been on the shelf for almost two decades.
Soon to be in a classified ad section near you! (again)

 

Not sure of my exact setup. The heads were bought from Scoggin-Dickey about tweny years ago. They came with the Scorpion rockers and I reused my original stock valve covers. Haven't experienced any fitment issues including when I replaced my valve cover gaskets.